Commit 096327a9 authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

Fix for DTLS DoS issue introduced by fix for CVE-2011-4109. 

Thanks to Antonio Martin, Enterprise Secure Access Research and
Development, Cisco Systems, Inc. for discovering this bug and
preparing a fix. (CVE-2012-0050)
parent cc10bcf2

CHANGES

+5 −1
Original line number Diff line number Diff line
@@ -4,7 +4,11 @@ 


 Changes between 0.9.8s and 0.9.8t [xx XXX xxxx]



  *)

  *) Fix for DTLS DoS issue introduced by fix for CVE-2011-4109.

     Thanks to Antonio Martin, Enterprise Secure Access Research and

     Development, Cisco Systems, Inc. for discovering this bug and

     preparing a fix. (CVE-2012-0050)

     [Antonio Martin]



 Changes between 0.9.8r and 0.9.8s [4 Jan 2012]

ssl/d1_pkt.c

+7 −10
Original line number Diff line number Diff line
@@ -336,6 +336,7 @@ dtls1_process_record(SSL *s) 
	unsigned int mac_size;

	unsigned char md[EVP_MAX_MD_SIZE];

	int decryption_failed_or_bad_record_mac = 0;

	unsigned char *mac = NULL;





	rr= &(s->s3->rrec);
@@ -403,19 +404,15 @@ if ( (sess == NULL) || 
#endif			

			}

		/* check the MAC for rr->input (it's in mac_size bytes at the tail) */

		if (rr->length < mac_size)

		if (rr->length >= mac_size)

			{

#if 0 /* OK only for stream ciphers */

			al=SSL_AD_DECODE_ERROR;

			SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);

			goto f_err;

#else

			decryption_failed_or_bad_record_mac = 1;

#endif

			}

			rr->length -= mac_size;

			mac = &rr->data[rr->length];

			}

		else

			rr->length = 0;

		s->method->ssl3_enc->mac(s,md,0);

		if (memcmp(md,&(rr->data[rr->length]),mac_size) != 0)

		if (mac == NULL || memcmp(md, mac, mac_size) != 0)

			{

			decryption_failed_or_bad_record_mac = 1;

			}